Re: [PATCH 1/1] powerpc/iommu: Enable remaining IOMMU Pagesizes present in LoPAR

From: Leonardo Bras
Date: Wed Apr 07 2021 - 15:58:35 EST


Hello Alexey,

On Tue, 2021-03-23 at 18:41 +1100, Alexey Kardashevskiy wrote:
[...]
> > +#define IOMMU_PAGE_SHIFT_16G 34
> > +#define IOMMU_PAGE_SHIFT_256M 28
> > +#define IOMMU_PAGE_SHIFT_128M 27
> > +#define IOMMU_PAGE_SHIFT_64M 26
> > +#define IOMMU_PAGE_SHIFT_32M 25
> > +#define IOMMU_PAGE_SHIFT_16M 24
> > +#define IOMMU_PAGE_SHIFT_64K 16
>
>
> These are not very descriptive, these are just normal shifts, could be
> as simple as __builtin_ctz(SZ_4K) (gcc will optimize this) and so on.
>
> OTOH the PAPR page sizes need macros as they are the ones which are
> weird and screaming for macros.
>
> I'd steal/rework spapr_page_mask_to_query_mask() from QEMU. Thanks,
>

Thanks for this feedback!
I just sent a v2 applying your suggestions.

Best regards,
Leonardo Bras